Double-acting pawl



y 1949. D. c PETERSON 2,477,140

DOUBLE-ACTING PAWL Filed Dec. 18, 1945 Patented July 26, 1949 1" OFFICE.

Y DOUBLE-ACTING PA L Donald 0. Peterson, Graceville, r Application December 18, 1945, Serial No. 635,697

This inventionrelates to a double acting pawl unit.

It is an objectof 'the inventionto provide a relatively simply constructedyet highly efficient double acting pawl particularly adapted for use in connection with an arcuate rack wherein the pawl can be readily shifted in either direction and wherein it is held in firm engagement with the rack when shifted to the desired position.

Another object of the invention is to provide a double acting pawl unit having spring influenced locking means which will positively insure maintenance of the pawl in its desired position.

A further object of the invention is to provide an improved pawl construction which is capable of many adaptations but it is of particular ad'- vantage in combination with. an actuating lever by means of which the pawl unit can be con nected'to a remotely positioned part to be adjustably moved. J

' The above and other objects and advantages of the invention will more fully vappear from the following description made in connection with'th'e accompanying drawings, wherein like reference characters refer to the same parts throughout the views, and, in which:

Figure 1 is a side elevation of a pawl and rack assembly with a portion of the pawl in section and the pawl controlling means in alternate positions in full and dotted lines;

Figure 2 is a side elevation of the opposite side of the unit from Figure 1 with the upper portion of the actuating lever broken away;

Figure 3 is a side elevation of the unit as viewed in Figure 1 with the side face and guide member in position and with upper portions broken away; and

Figure 4 is a longitudinal vertical sectional View through the unit.

There is illustrated in Figure 1 a portion of a horizontal member 5 which may be a portion of a machine frame of any type.

Secured to the frame member 5 is an arcuate toothed rack 6 whose spaced teeth I lie about the curved portion thereof. The rack is secured by nutted bolts 8 and 9 to the frame 5.

Pivotally mounted to the lower central portion of the rack 6 as at I is a lever I I terminating at Ila. Intermediate the ends of the lever II is a cross member I2 having a horizontal web I3 extending therefrom, said web I3 being cut away to provide a central opening [4 as best shown in Figure 1. Secured to the edge of the web I3 and extending above and below the same is a side plate l mounted upon nutted bolts l5 which 4 Claims. (01. 74-536) extend through the cros's' me'mber 'I2, and the side plate I5 is provided with an inwardly extending tongue I1 which bears against the lever II. Therefore, the side plate I5 is spaced from the'cr-oss member I2 by reason of the web I3 and the tongue II. Lying between the cross member [2 and the side plate I5 isa pawl element I3 having a medial downwardly extending portion I9 shaped to lie between the teeth I on the rack G. Extending laterally in opposite directions from the medial portion of the pawl IB are hooked arms which are adapted to overlie and be supported by bolts I6. 'As' shown in Figure 1, the pawl 'el emen't'jl fl lies'loosely in the frame or casing'provided by the crossmember' I2 and the side plate I5 so that the pawl'can rock with one of the armsZfl or the otherm ovingupward away from its supporting bolt I6.

Pivotally connected to the upper end of the lever I I and extending considerably thereabove is an actuating member 22. The lower end of said actuating lever 22 is provided with a pair of spaced cam arms 23 which lie at either side of the tongue IT 'on the side plate I5 and extend below the upper edge of said side plate l5 into close proximity with the upper rounded portions Of the cam arms 20.

Mounted on each of the two bolts I5 is a bowed spring 24 and each spring is provided with a horizontally bent upper end 25, best shown in Figure 4. The upper spring ends 25 are adapted to engage opposite edge portions of the lever II and the second lever 22 and the springs function to normally maintain the lever 22 in alignment with the lever I I.

When the device is in the full line position of Figure 1 the spaced cam arms 23 have their lower ends lying closely adjacent each of the arms of the pawl I8, thereby preventing the pawl from rocking away from either of its supporting bolts I6 and securely retaining the central tooth I9 of the pawl [8 between two of the teeth 'I on the rack 6. When it is desired to move the pawl I8 relative to the rack the longer lever 221s shifted such as to the dotted line position of Figure 1. This keeps the left hand cam arm 23 in close proximity with the left hand pawl arm 20, but it moves the right hand cam arm 23 away from the right hand pawl arm 20. The rack tooth I which lies to the left of the pawl tooth I9 will exert a lateral pressure or resistance to movement of the tooth I9 and the entire pawl I8 will swing upwardly about the left hand supporting bolt It to the dotted line position of Figure 1. Thus it will be seen that the pawl will move freely along the toothed rack until the lever 22 is released, the springs 24 realign the levers 22 and II and the right hand cam arm 23 again moves down into contact with or close proximity to the right hand pawl arm 20, whereupon the pawl tooth I9 is again locked in position on the toothed rack Ii.

Naturally, the lever 22 can be swung to the right amp the action will he merseirtwpermit movement? oi tfie'iiefw' l ufiit in die-opposite diiec: tion since the pants are duplicated on either side in the directions of movement of the pawl.

It will, of course, be understood that various changes may be made in the form, attains as": rangement and proportions of the variom parts without departing from the scope of inv'ehtion.

WhatIclaimis: r

1. A double acting pawl unit for use with a toethedrack comprising, a pawl element having medial portion aeitpteaito as eset-rear etween me than or a rack: said 'fiafw l" ieriiestnav ng aims e zitefidi'nfg'fioiii oppasitesizies or saidiiieclial portra t, reiatweiif stationawifiearn'rcrsupportin'g's iid" pawl element for tilting; mqvemnt relaare thereto, sming'ly'ieiaiatig noma s "said pawl against support ng iiie'iffs; a "s'iii fable paw s'cdring ifi'e'fiilii which, in biie position meteor, provides a s'tdp'wiiicn' restraifi s both areas? said pawl against movement mat-riser said'isiipp'ortdig and said stffciiriiigimffibr; iii shifted fiositio'fistlieretftf either side'ogsamf first medtioned 565mm, re easing ass ortiie otherof'said pawl-- arnis respectiwt' fhY'iiidVii'ffi'lf away from itsfsfipfiqftiifg'fii'eiajfisi V a said pawl and being shiftable by said lever to selectively release either arm of said pawl and permit rocking of the pawl, and a spring device connected between said frame and said securing member and normally centering said securing member relative to said pawl arms.

3. A double acting pawl unit for use with a toothed rack comprising, a frame, a pawl element roekablyi supporteddmsaid-firame and haviiig medial portion adapted to wrete'ived between the teeth of a rack, said pawl element having arms extending laterally in opposite directions from the medial portion of said pawl, a splii'igfieliiably urging said pawl in a rack engaging direction; a shiftable pawl securing member located closely adjacent the arms of said pewtsalti paws siifii ing member in a first position thereof, holding said pawl arms against rhl'iiiig movement, and said securing member being shiftable to either" side of said first position to aaematelt riease s'aill paw-1' topermit selective rocking movement of the pawl, antenna means for and securing" nitrates coinpnsi'fig'a device geometric-saidiraine aiid efigagmg sear seciifihg member.

'4. "1l"i m tt-"are 'iri' eiaifir 35 and said spring aetieeesmnnsmg a sifting ai-ims eat-end: ing'freifi samir-ramets op osite sides afield pawi seeming menisci and b ing forested syiiifiietri calla relative to said foclfahlepaw element.-

, The idlbwifig referent's are of record iii the 

